2.7 -- Rigging model and not seeing "Deform" section in Armature >> Object Data >> Skeleton
The deform section is one icon over from where you are in that picture, on the properties panel.  Click on the 'bone' icon, the deform will be there.  By the way, that tutorial is out of date, and you might just want to uncheck the VG group in your armature modifier settings to get full deformations going.